prototype() with no arguments

[p5pRT]

Migrated from rt.perl.org#123514 (status was 'resolved')

Searchable as RT123514$

[p5pRT]

From @cpansprout

prototype() is not documented as accepting no arguments. But it does accept no arguments, and corrupts the stack in the process​:

$ ./perl -Ilib -le '$,=" "; print 1,2,3,prototype(),4,5,6'
1 2 4 5 6

Here, it steals 3 from the stack and replaces it with undef. Here is a more intriguing example​:

$ ./perl -Ilib -le 'print "CORE​::undef", prototype()'
;\[$@​%&*]

Should prototype() be illegal? Or should it mean prototype($_)?

--

Father Chrysostomos

[p5pRT]

From @rgs

On 28 December 2014 at 23​:17, Father Chrysostomos
<perlbug-followup@​perl.org> wrote​:

prototype() is not documented as accepting no arguments. But it does accept no arguments, and corrupts the stack in the process​:

$ ./perl -Ilib -le '$,=" "; print 1,2,3,prototype(),4,5,6'
1 2 4 5 6

Here, it steals 3 from the stack and replaces it with undef. Here is a more intriguing example​:

$ ./perl -Ilib -le 'print "CORE​::undef", prototype()'
;\[$@​%&*]

Should prototype() be illegal? Or should it mean prototype($_)?

Well, according to itself, it requires one argument​:

perl -E 'say prototype"CORE​::prototype"'
$

which is probably an implementation detail. I see no strong objection against
allowing a default topic for it

[p5pRT]

The RT System itself - Status changed from 'new' to 'open'

[p5pRT]

From j.imrie1@virginmedia.com

On 28/12/2014 22​:17, Father Chrysostomos (via RT) wrote​:

# New Ticket Created by Father Chrysostomos
# Please include the string​: [perl #123514]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=123514 >

prototype() is not documented as accepting no arguments. But it does accept no arguments, and corrupts the stack in the process​:

$ ./perl -Ilib -le '$,=" "; print 1,2,3,prototype(),4,5,6'
1 2 4 5 6

Here, it steals 3 from the stack and replaces it with undef. Here is a more intriguing example​:

$ ./perl -Ilib -le 'print "CORE​::undef", prototype()'
;\[$@​%&*]

Should prototype() be illegal? Or should it mean prototype($_)?

I'd go for the latter, prototype($_), in line with oct(), say(), print()
etc

[p5pRT]

From @cpansprout

Fixed in eb4ec35 to infer $_.

--

Father Chrysostomos

[p5pRT]

@cpansprout - Status changed from 'open' to 'resolved'

[p5pRT]

From @rjbs

* Father Chrysostomos via RT <perlbug-followup@​perl.org> [2014-12-28T19​:46​:19]

Fixed in eb4ec35 to infer $_.

+1

--
rjbs